1. Field of the Invention
This invention relates to the localized removal of a precious metal inlay from a metal strip. In particular, the invention relates to the removal at predetermined positions of a narrow precious metal inlay extending along a metal strip from which terminals are formed, by the use of a broaching tool.
2. Related Art
In telecommunications systems and other electrical and electronic systems, electrical connections are made between cooperating terminals. Particularly, one such connection is between a pin and a female or box terminal. To obtain a high quality connection, small dimples are formed on the contact members. These dimples have been formed in various ways. For example, one way is by spot welding a gold wire in place, cropping and forming. Another way is to locally form a dimple and then gold plate. It is very difficult to restrict the gold plating to the dimple and expensive apparatus is required. In yet another way, a gold stripe is inlayed into a strip of contact metal, for example copper. However, with this latter method a substantial amount of gold remains with the scrap and at unrequired positions of the terminal, after forming the terminals. At the same time the percentage of gold relative to the total scrap is quite low and recovery costs are therefore high.
Instead of forming a dimple in the base strip it has also been proposed to weld a narrow stripe of gold along the strip of contact material, remove the unwanted gold to leave localized pieces of stripe and then form these localized pieces. However the thickness of gold is much greater than necessary and the comparative cost is higher. It is relatively easy to remove the unwanted gold as it projects above the surface of the strip of contact material. This convenience is offset by the more expensive spot formation.